161155551 has 8 divisors (see below), whose sum is σ = 216960640. Its totient is φ = 106393752.

The previous prime is 161155537. The next prime is 161155571. The reversal of 161155551 is 155551161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161155551 - 2⁶ = 161155487 is a prime.

It is a super-2 number, since 2×161155551² = 51942223236227202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161155571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260461 + ... + 261078.

It is an arithmetic number, because the mean of its divisors is an integer number (27120080).

Almost surely, 2^161155551 is an apocalyptic number.

161155551 is a deficient number, since it is larger than the sum of its proper divisors (55805089).

161155551 is a wasteful number, since it uses less digits than its factorization.

161155551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521645.

The product of its digits is 3750, while the sum is 30.

The square root of 161155551 is about 12694.7056287257. The cubic root of 161155551 is about 544.1873262290.

The spelling of 161155551 in words is "one hundred sixty-one million, one hundred fifty-five thousand, five hundred fifty-one".